During many types of exercise, your body uses stored carbs to provide you with energy ().

In the body, carbohydrate stores are called glycogen. This glycogen is mostly found in two places: your liver and muscles ().

Carb loading is simply a nutritional strategy to increase the glycogen stored in your body above its normal amount ().

This typically involves several days of eating more carbs than usual while also decreasing exercise to reduce the amount of carbs you are using.

The number of carbs you can eat ranges from 2.3–5.5 grams per pound (5–12 grams per kg) of body weight per day. If you weighed 154 pounds (70 kg), that would work out to 350–840 grams of carbs per day ().

People often use carb loading before certain athletic events or competitions because of the importance of carbs as a fuel source during exercise ().

However, it only improves performance for certain types and durations of exercise.

Specifically, it may be appropriate for exercise that leads to large decreases in the amount of glycogen in your muscles, such as prolonged biking or running (, ).

In these types of exercise, fatigue can occur when glycogen levels get too low ().

Research has shown that carb loading may reduce fatigue and improve performance by 2–3% for exercise lasting more than 90 minutes ().

However, it is probably not effective for shorter durations of exercise or types of exercise that involve short bursts of activity, including weight training (, , ).

Summary Your body stores carbs in the form of glycogen. Carb loading is a strategy to increase your glycogen stores and improve exercise performance. It may be effective in events lasting more than 90 minutes, but it's probably unnecessary for shorter durations.

During days four to six of this program, you consume a high-carb diet that gets about 70% of its calories from carbs. You also reduce exercise on day four and perform no exercise on days five and six.

Although experts once believed the initial “depletion” phase helped the body produce more glycogen once carbohydrates were eaten again, newer research shows it may not be necessary ().

6-Day

For the first three days, this program involves eating a moderate-carb diet that gets about 50% of its calories from carbs. This is followed by three days of a high-carb diet, with about 70% of calories from carbs ().

Throughout these six days, you gradually decrease the amount you exercise. During days four to six, you only perform 0–20 minutes of exercise per day.

Classic 3-Day

This program is shorter and simpler than the six-day programs.

At the beginning of the three days, you perform one exercise session until your body is exhausted ().

For the remainder of the three days, you perform no exercise while consuming a high-carb diet that gets about 70% of its calories from carbs.

Modified 3-Day

This program is identical to the classic three-day program, but you do not perform the exercise session at the beginning.

Instead, you simply do not exercise for three days, while increasing the number of carbs you eat ().

Research on this program used a carbohydrate intake of 4.5 grams per pound (10 grams per kg) of body weight per day. This would be about 700 grams of carbs if you weighed 154 pounds (70 kg).

1-Day

The one-day program is the simplest of them all.

You do not exercise for one day, and you consume a high-carb diet of about 4.5 grams per pound (10 grams per kg) of body weight ().

Summary There are several specific carb loading programs. The major differences between them are their durations and the amounts of exercise they include. All programs use a short-term high-carb diet while temporarily decreasing exercise.

Before you start a carb-loading program, there are several common carb-loading mistakes you should be aware of.

Carb Loading When You Don't Need To

One major mistake is using carb loading when you don’t need to.

Research has found it can be beneficial for exercise lasting more than 90 minutes ().

However, there may be no benefit for slightly shorter durations of exercise, including events lasting 60–90 minutes (, ).

What’s more, it is probably unnecessary for weight training or other exercise involving short bursts of activity ().

Some research found that carb loading with 3 grams per pound (6.5 grams per kg) of body weight each day did not improve performance on an explosive jump squat exercise, compared to 2 grams per pound (4.4 grams per kg) ().

Other studies showed that carb loading did not improve performance during high-intensity cycling lasting less than 20 minutes (, ).

If you are recreationally active but don’t compete or perform long training sessions, carb loading is probably not necessary for you.

What’s more, if you carb load when you don’t need to, you may end up changing your normal diet unnecessarily or consuming more calories than your body needs.

Eating Too Much Fat

While fat can be part of a balanced diet, it may be beneficial to limit how much of it you eat during carb loading ().

Since you’re increasing your carb intake, reducing your fat intake can help you avoid eating too many calories. Eating too much could cause weight gain or leave you feeling sluggish.

Some people make the mistake of choosing foods that are high in both carbohydrates and fat, rather than just carbs.

For example, many desserts such as chocolate, ice cream and cookies fall into this category, as well as creamy pasta sauces and buttery breads.

When you’re carb loading, it may be best to choose high-carb foods that are low in fat to avoid consuming too many calories. Checking the nutrition information of foods you eat can help.

Eating Too Much Fiber

Eating high-fiber foods could also be detrimental. Although fiber is part of a healthy diet, too much fiber during carb loading can cause stomach discomfort in some individuals ().

Carb loading is a unique time when it could be better to choose white bread or pasta over whole wheat. During this time, you should probably also avoid high-fiber foods like beans.

Overall, it may be best to choose lower-fiber carbohydrate sources to avoid the possibility of fullness or stomach discomfort during exercise.

As with low-fat foods, you can check the nutrition information on foods you eat to be sure they aren’t high in fiber.

Eating the Wrong Amount of Carbs

Another possible mistake is not knowing if you are eating the right amount of carbohydrates. Without recording what you eat, you may be eating too much or too little.

Experts often recommend that people who are carb loading eat 2.3–5.5 grams of carbs per pound (5–12 grams per kg) of body weight per day. Recording your food intake can help you make sure you are eating the right amount ().

If you don’t eat enough carbs, this means you didn’t carb load, even if you thought you did.

However, if you eat more carbs than necessary, you may have changed your diet too much or simply eaten too many calories.

In the end, it is best to record your food intake and calculate how many carbs you’re eating.

As your experience grows, you may not need to do this anymore. However, it is a good idea for beginners.

Eating New or Unusual Foods

It can be a mistake to introduce new or unusual foods during carb loading.

The days before your event or competition are important, and having an upset stomach due to unfamiliar foods can spoil your experience and exercise performance.

Because of this, you should choose foods that are familiar to you — in addition to being high-carb, low-fat and low-fiber.

Exercising Too Much

Lastly, failing to decrease or “taper” the amount of exercise you perform during carb loading could limit the extent to which your glycogen stores increase during your high-carb diet.

Summary Common mistakes include carb loading when you don’t need to, choosing foods that are too high in fat or fiber, not knowing how many carbs you are eating, introducing new or unusual foods and failing to taper the amount you exercise.

If you are considering using carb loading before an upcoming competition or athletic event, there are a few things you should think about.

Make Sure You’ll Actually Benefit from a Carb Load

Before you launch into carb loading, consider whether the type and duration of exercise you are doing requires it.

If you will be performing exercise lasting more than 90 minutes without breaks, such as running or cycling, you may benefit from this nutrition strategy.

If your exercise is shorter or involves many breaks, such as weight training, carb loading is probably not necessary.

Figure Out How Many Carbs You Typically Consume

If you record all the food you eat for several days using a food-tracking app or the nutrition labels on your food, you can calculate your current daily carbohydrate intake.

Then you can divide the grams of carbs you eat each day by your weight to compare your current intake to carb loading recommendations.

For example, if you weigh 154 pounds (70 kg) and you normally eat 300 grams of carbs per day, then you are consuming 1.9 grams per pound (4.2 grams per kg) of carbs per day.

People who are carb loading may eat 2.3–5.5 grams of carbs per pound (5–12 grams per kg) of body weight per day. That said, experts often recommend a more limited range of 3.6–4.5 grams per pound (8–10 grams per kg) (, ).

Based on these recommendations, you would need to eat approximately double the amount of carbs you would normally.

Make Sure to Increase Only Carbs, Not Fat

Remember that when you increase your carb intake, you may need to decrease your fat intake so that you don’t eat too many calories leading up to your event.

Avoid choosing foods that are high in both carbs and fats, such as desserts, pasta with creamy sauce, pastries and similar items.

Choose the Duration of Your Carb Load

As discussed, carb loading programs can last from one to six days. It may be a good idea to start with a simple program lasting between one and three days.

For example, you could simply increase your carb intake to around 3.6 grams per pound (8 grams per kg) of body weight per day and decrease your exercise one to three days before your event.

You could also practice several different types of carb loading during training and keep notes to decide which helped you feel and perform your best.

Generally, it is best to experiment during your training rather than right before a real competition. That way, you can decide what will work best before your big event.

Focus on Familiar Foods

Lastly, it may be best to focus on familiar foods during carb loading. Unusual foods could upset your stomach and impair your performance.

Once you have your nutrition plan set, you need to remember to taper your exercise in the days leading up to your event or competition.

The combination of eating more carbs and using less of your body’s carb stores will help produce the highest levels of glycogen in your body.

Summary Before you start carb loading, consider whether you will benefit from it. You should also figure out how many carbs you normally eat so you know how much to change your regular diet. Deciding the right duration for carb loading is also important.

To get the recommended amount of carbohydrates, you should focus on foods that are high-carb, low-fat and don’t have too much fiber.

Foods to Eat

Low-fiber cereals

Fruit juices

White noodles with marinara sauce

White bread

Fruit jelly

White rice

Fruit smoothies

Skinned white potatoes

Applesauce

Pretzels

Fruit, including bananas, oranges and watermelon

White flour, used in cooking

Sherbet or popsicles

Sports drinks

Low-fat energy bars

Of course, it is also important to have protein to support your muscles. Try to focus on lean protein sources, such as fish, lean cuts of meat or poultry and fat-free dairy.

What’s more, eat foods you enjoy and that are familiar to you. Try to find the best compromise between the recommendations and foods you enjoy.

Many people eat high-carb foods that are high-fat too. It is best to avoid these during carb loading.

Foods to Avoid

Below are some examples of foods that may seem high-carb but are also high-fat and therefore inappropriate for carb loading.

Creamy sauces, such as Alfredo sauce

Muffins

Crackers

Chips

Cookies

Pizza

Brownies

Ice cream

Pastries

French fries

Donuts

Certain energy bars

Also, many foods that are a great part of your normal diet may be high in fiber. You should limit or remove these foods from your diet during carb loading.

They include:

Beans

Lentils

Split peas

Whole-wheat pasta

Bran flakes

Oatmeal

Raspberries

Artichoke

Green peas

Chickpeas

Chia seeds

Broccoli

These lists are not comprehensive. To find the best high-carb options for your diet, check the nutrition information for the foods you normally eat.

Summary During carb loading, you should focus on eating high-carb, low-fat and low-fiber foods that are familiar and enjoyable. Using the lists above can get you started, but you should also review the nutrition facts for your favorite foods.